[Xapian-discuss] Performance of range searches

[Alex Neth]

I seem to be using 1.0.5 which the latest version available from the  
site I was linked to last week.'


--
Alex Neth
Liivid Inc / CribQ
www.liivid.com / www.cribq.com
alex at liivid.com
+1 206 499 4995
+86 13761577188








On Oct 31, 2008, at 9:14 PM, Olly Betts wrote:

> On Fri, Oct 31, 2008 at 04:41:15PM -0700, Alex Neth wrote:
>> Is there any way to improve the performance of range searches?
>
> You didn't say which Xapian version you're using.  One of the  
> changes in
> 1.0.7 improves value range performance in some cases, so make sure
> you're using 1.0.7 or newer.
>
> There are improvements to how values are stored in the development
> "chert" backend in SVN trunk.  This isn't taken full advantage of by
> value ranges yet, but once that's also fixed, you should find they're
> lots faster than currently.
>
> With 1.0.x there are a couple of tricks to help improve the speed  
> (these
> will be irrelevant for Xapian >= 1.1.0).  Firstly, make sure that you
> aren't storing any values which you don't actually use currently  
> (1.0.x
> has to retrieve all values for a document just to get one).  And
> secondly store the most speed critical values in the lower numbered
> value slots (1.0.x has to unpack the values for a given document
> linearly to get the one it wants).
>
> Cheers,
>    Olly